HANCOCK COUNTY – Chemicals flood the brain, and in an instant, a rush of enjoyment follows.

What caused the reaction could be any number of things: a forkful of chocolate cake, a kiss from the person you love, the opening notes of your favorite song.

Dopamine, one of the brain’s chemical messengers, is involved in dozens of vital functions including breathing and walking. The hormone also rewards behavior with an enjoyable feeling.

The brain has a system in place to check how much dopamine is released and at what speed. But when someone takes opioids, which are prescription painkillers or heroin, those safeguards are lost. The hormone floods the body, uncontrolled, like a car gaining speed as it travels down a hill.

“There are no brakes anymore; it only accelerates,” said Dr. Ruben Baler, a neuroscientist and health science administrator for the National Institute on Drug Abuse.

Dopamine’s impact on the body is the key to understanding the runaway effect opioids have on the body. Each dose of the drug causes a biological reaction. Pathways in the brain are altered, which drives behavior and continued use of the substance.

Powerful opioids such as heroin, fentanyl and oxycodone re-circuit the brain so quickly that a person becomes dependent. For doctors and researchers studying the ongoing opioid epidemic, it is clear addiction to these drugs is driven by biology, not a moral or personal failing.

“The parts of the brain that help us consider cause and effect come offline in addiction,” said Dr. Joseph Niezer, a psychiatrist with Franciscan Health Network Psychiatric Specialists in Indianapolis. “There are identifiable changes in the brain of someone dealing with addiction, the same way there are changes with someone who had Parkinson’s disease or Alzheimer’s disease.”

It’s an illness

Addiction is officially recognized as a brain disease, a chronic, relapsing condition in which a person compulsively seeks out and uses drugs despite continued harmful consequences, according to the American Society of Addiction Medicine.

Estimates from the National Institute on Drug Abuse report that 2.6 million people suffer from substance use disorders related to prescription opioid pain medications and heroin.

But many more people take medication as prescribed and have no problems stopping using, or even in some cases do misuse those drugs but do not become addicted. Others people are at a genetic disadvantage to become dependent, Baler said.

“Just talking about one gene, and there are thousands of genes that we can talk about that can impact it,” Baler said. “Individually, these gene differences are not huge. But if you add them up, you are building up personalities that are more likely to engage in drug abuse, and once they’re exposed to that, they’re more likely to repeat the experience over and over again.”

Environment can also impact who falls into addiction. People who suffer from chronic sleep deprivation have a lowered ability to regulate dopamine.

People who have dealt with chronic pain and have taken legal, prescribed opioid medications can find their bodies becoming more and more tolerant of the substances. The same dosage that used to relieve their pain no longer does, and side effects such as nausea and vomiting are lessened. As the impact the drugs have on the brain decreases, higher doses are required, which can also eventually lead to dependence, Baler said.

“All of these things — genetic and environment — react in very complex ways. The result is this huge range of individual differences in the people who, once exposed to those drugs, who want to repeat this experience and risk becoming addicted to it,” Baler said.

‘It’s not who he was’

They found Cord Tucker dead on a Sunday morning in the bathroom of his parents’ Greenfield home.

Stints in rehab, run-ins with the law – nothing could break heroin’s hold on him.

He was 28.

A lethal dose of heroin laced with fentanyl — a synthetic opioid that’s said to be 50 to 100 times more potent than morphine — ended a seven-year battle with addiction, one that started with drinking and smoking marijuana as a teen and eventually grew to more addictive substances.

Nights in jail and stays in halfway houses didn’t help him. He went to rehab three times in as many years before his family members decided to create a makeshift treatment program of their own, one where they served as his strongest support system as well as his strictest disciplinarians.

They took his money away so he couldn’t buy drugs, only doling out what he needed for a trip to the store and no more, and they watched his phone and social media accounts to make sure he wasn’t contacting dealers or friends he knew would have drugs — all while struggling with their own misunderstandings of why he couldn’t stop using on his own.

Tucker’s stepfather, Dave Brown, spoke to the Daily Reporter after his stepson’s overdose. He said he always believed tough love would help his stepson get clean, until one day when he watched the young man break down in despair.

Tucker fell to the floor, arms outstretched, begging for understanding.

Look at me, Tucker had said to Brown; can’t you see I don’t want to be like this?

And Brown listened – really listened for the first time, he said – as his son described how the drugs made him feel, how something inside him changed when he was on them, how he would give anything to make that feeling go away forever.

“If I had a do-over, I would have done it with more love and more grace,” Brown said. “My son did not choose this. He didn’t want it. It’s not who he was.”

An ingrained response

The impact that opioids have on the brain stems from the way humans have evolved, Baler said.

The brain has evolved over millions of years to help drive and encourage survival of our species. For example, eating, reproducing and taking care of the young can all provoke the release of chemicals, particularly dopamine, to make a person feel good.

If you feel enjoyment after eating or having sex, you’re going to keep doing it, which allows humans to persist as a species, Baler said.

“There is a very primitive, very robust system that rewards behaviors that we want to be repeated, because natural response reinforces that for survival,” he said.

Evolution has provided a mechanism for humanity to survive over tens of thousands of years, but it does not occur quickly, Baler said. Elements of the environment we live in — the activities we take part in, the entertainment we watch and the substances we consume — are rapidly changing.

That environment can provide rewards to the nervous system much greater than what the brain was designed to handle.

Baler compared the natural release of dopamine for different activities on a one to 10 scale. Eating a delicious meal or having a fun night out with friends will raise dopamine levels somewhere in that natural range.

The brain operates on a kind of biological thermostat, adjusting how the hormone is released and never letting that level get too high, Baler said.

Different drugs can throw the entire system in chaos.

“Things such as amphetamine and opioids can trigger that dopamine well beyond anything evolution has ever intended, to a magnitude of 100 or 1,000,” Baler said. “The thermostat now is at risk, because it hasn’t been designed to deal with these values of dopamine.”

Opioids in particular short-circuit that system, blocking a chemical called a receptor that would check dopamine production. The drugs take away the natural abilities of the brain to curtail the release of dopamine. When someone takes heroin, morphine or another drug of this type, dopamine production runs uncontrollably.

Such high levels of dopamine in the brain warp the natural tolerance for the chemical and the biological urge is to replicate that feeling. The only way to do so is with an opioid such as vicodin or oxycodone, powerful painkillers available by prescription only.

Heroin, a highly addictive street drug derived from morphine, also achieves the same effect but is much cheaper to buy.

The ability of those drugs to spike dopamine to abnormally high levels is what leads to addiction, Baler said.

‘You have to have it’

Addiction is classified as a disease because the substances can change the structure of the brain and how it works with repeated use.

Opioids such as heroin, fentanyl and carfentanil are so powerful that addiction can form more quickly and in smaller doses, said Kim Manlove, retired director of the Indiana Addictions Issues Coalition.

“The more you use it, it causes more intense feelings of pleasure,” he said. “It gets to the point where you just want to use it over and over again.”

The drugs also shape the brain’s memory center, inhibitions and motivational systems, essentially hijacking the entire function of the brain to focus on the next hit.

In particular, the motivation center of the brain is impacted. That primitive area of the brain is rewired so the drug is as important as food, water, breathing — those things the brain tells the body are needed to keep us alive. That’s why people keep using it, despite the consequences. They can rationalize their drug use, Niezer said.

“Addiction is really the using despite the negative consequences. There are plenty of people who take opioids and are not overusing them or continuing to use them despite the consequences,” Niezer said. “With people who are addicted, even though this drug is causing all the problems in this person’s life, there’s this thought that if they use, everything will be OK.”

The way that opioids change the brain doesn’t just make addiction possible; it also makes relapsing once you try to quit much more likely.

Addiction can impact people for their entire lives, Manlove said.

“Your brain actually craves it and wants it and overrides the other parts of the brain that (say) you really shouldn’t do it,” he said. “You need to have it; you have to have it.”

Recovery doesn’t move in a straight line, Wheeler said. You don’t decide to be clean, and then it’s all upward trajectory; there will be stumbles, and between 40 and 60 percent of people who receive treatment for drug addiction will relapse, according to the National Institute on Drug Abuse.

“You can’t necessarily put a success rate on addiction. You can’t measure one person’s success on getting past addiction on another person,” she said. “Relapse is a part of recovery.”

Breaking through those intense cravings, and helping people repair their changed brains so that they don’t need to go back to the drugs, requires extensive long-term treatment, including medications, counseling and support.

Part of the reason the U.S. is seeing such a crisis with opioids is that historically, the treatment model has focused on short-term inpatient care, rather than treating a chronic disease, Manlove said.

They go to detox, they quit the drug, and they receive some short education about addiction. Then, they are referred to 12-step programs or other groups that, while effective for some, don’t provide the same level of care, including medication, that is needed to overcome the disease.

“We don’t do that with other chronic medical diseases like diabetes and cancer. If you’re diagnosed with cancer, you get radiation and drugs and five years of annual checkups and continuing care,” Manlove said. “But historically, (addiction) has been a shame-based disease, that it’s a personal choice and they’re doing this because they want to.”

What to know

What is an Opioid?

Opioids are a class of drugs that interact with specific receptors on nerve cells in the brain that control pain and emotion. These include illegal drugs such as heroin as well as pain relievers such as OxyContin, Vicodin, codeine and morphine, which are legal with a prescription but can be misused.

What is Heroin?

This illegal drug is made from morphine, a natural substance found in the seed pod of various opium poppy plants. Typically a white or brown powder, as well as a black, sticky substance, it can be injected into veins with a needle or snorted.

What is Fentanyl?

Developed as a prescription pain reliever, this drug is similar to morphine but is 50 to 100times more powerful. Fentanyl is typically prescribed to treat patients with severe painthrough injection, a skin patch or lozenge, and goes by the brand names Actiq, Duragesic and Sublimaze.

Street names include Apache, China Girl and Dance Fever, and in its illegal form, can be swallowed, snorted or injected, as well as put on blotter paper to be absorbed through the mouth.

What is Carfentanil?

Carfentanil is a drug derived from fentanyl and is 10,000 times more potent than morphine. The drug is not approved for use in humans in any way and is typically used inveterinary medicine to treat pain in large animals such as elephants.

It is too powerful for people unless they’ve developed a tolerance for heroin or fentanyl,and even then, a dose the size of a grain of salt can lead to overdose. The drug has been found in heroin and illegal doses of fentanyl.

In the coming year, a Daily Reporter special series will examine the public health crisis of opioid misuse.

Addicted & Dying will bring you firsthand accounts of people still battling drug addiction and tell the stories of families who lost someone they held dear.

We will talk to those on the front lines — the doctors, first responders, addiction specialists and more — about the problem straining social service agencies, hospitals, the court system and the economy.

And beyond that, Addicted & Dying will explore what treatments and approaches work, what communities can do to help people in need.

Have an idea for our project? Contact us at dr-editorial@greenfieldreporter.com.